Light-emitting structure

ABSTRACT

A light-emitting structure includes a first epitaxial unit; a second epitaxial unit disposed next to the first epitaxial unit; a crossover metal layer including a first protruding portion laterally overlapping the first epitaxial unit and the second epitaxial unit wherein the first protruding portion is electrically connected with the first epitaxial unit and the second epitaxial unit; a conductive connecting layer disposed below the first epitaxial unit and the second epitaxial unit and surrounding the first protruding portion; and an electrode arranged on the conductive connecting layer.

REFERENCE TO RELATED APPLICATION

This application is a continuation Application of U.S. Ser. No.14/954,708 entitled “LED ARRAY”, filed on Nov. 30, 2015 which is adivisional Application of U.S. Ser. No. 14/330,914, entitled “LEDARRAY”, filed on Jul. 14, 2014, now pending, which is a division of U.S.patent application, Ser. No. 14/065,330, entitled “LED ARRAY”, filed onOct. 28, 2013, issued on Jul. 15, 2014, which is a division of U.S.patent application, Ser. No. 13/428,974, entitled “LED ARRAY”, filed onMar. 23, 2012, issued on Oct. 29, 2013, which claims the right ofpriority based on Taiwan patent application Ser. No. 100110029, filed onMar. 23, 2011, the entireties of which are incorporated by referenceherein.

TECHNICAL FIELD

The application relates to a light-emitting structure, and moreparticularly to a light-emitting structure having protrusion portion.

DESCRIPTION OF BACKGROUND ART

Recently, based on the progress of epitaxy process technology, thelight-emitting diode (LED) becomes one of the potential solid-statelighting (SSL) source. Due to the limitation of physics mechanism, LEDscan only be driven by DC power source. Thus the regulator circuit, buckcircuit, and other electronic devices are necessary for every lightingdevice using LED as lighting source to convert AC power source into DCpower source to drive LED. However, the addition of the regulatorcircuit, buck circuit, and other electronic device raises the cost oflighting device using LED as lighting source and causes the low AC/DCconversion efficiency and the huge lighting device package also affectthe reliability and shorten the lifetime of LED in daily use.

SUMMARY OF THE DISCLOSURE

The present application discloses a light-emitting structure including afirst epitaxial unit; a second epitaxial unit disposed next to the firstepitaxial unit; a crossover metal layer including a first protrudingportion laterally overlapping the first epitaxial unit and the secondepitaxial unit wherein the first protruding portion is electricallyconnected with the first epitaxial unit and the second epitaxial unit; aconductive connecting layer disposed below the first epitaxial unit andthe second epitaxial unit and surrounding the first protruding portion;and an electrode arranged on the conductive connecting layer.

The present application discloses a light-emitting structure including alight-emitting unit; a crossover metal layer comprising a protrudingportion laterally overlapping the light-emitting unit, wherein theprotruding portion is electrically connected with the light-emittingunit; a conductive connecting layer disposed below the light-emittingand surrounding the protruding portion; and an electrode arranged on theconductive connecting layer; wherein a top surface of the protrudingportion contacts a surface of the light-emitting unit or the protrudingportion is devoid of passing through the first epitaxial unit.

The present application discloses an LED array comprising a permanentsubstrate, a bonding layer on the permanent substrate, a secondconductive layer on the bonding layer, a second isolation layer on thesecond conductive layer, a crossover metal layer on the second isolationlayer, a first isolation layer on the crossover metal layer, aconductive connecting layer on the first isolation layer, an epitaxialstructure on the conductive connecting layer, and a first electrodelayer on the epitaxial structure.

The present application further discloses an LED array comprising apermanent substrate, a bonding layer on the permanent substrate, a firstconductive layer on the bonding layer, a second isolation layer on thefirst conductive layer, a crossover metal layer on the second isolationlayer, a first isolation layer on the crossover metal layer, aconductive connecting layer on the first isolation layer, and anepitaxial structure on the conductive connecting layer.

The present application further discloses an Led array having Nlight-emitting diode units (N≧3) and the light-emitting diode units areelectrically connected with each other by the crossover metal layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1I are the cross sectional views of the LED array in accordanceof the first embodiment of present application.

FIGS. 1A′-1G′ are the top views of the first embodiment of LED arraydisclosed by present application.

FIGS. 2A-2I are the cross sectional views of the second embodiment ofLED array disclosed by present application.

FIGS. 2A′-2G′ are the top views of the second embodiment of LED arraydisclosed by present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present application discloses an LED array having N light-emittingdiode units (N≧3) comprising a first light-emitting diode unit, a secondlight-emitting diode unit in sequence to the (N−1)^(th) light-emittingdiode unit and an N^(th) light-emitting diode unit. The LED arrayfurther comprises a first area (I), the second area (II), and the thirdarea (III). The first area (I) comprises the first light-emitting diodeunit, the third area (III) comprises the N^(th) light-emitting diodeunit, and the second area (II) locates between the first area (I) andthe third area (III) and comprises the second light-emitting diode unitin sequence to the (N−1)^(th) diode units.

The first embodiment discloses a first LED array 1 having threelight-emitting diode units. FIGS. 1A to 1I illustrate the crosssectional views and the FIGS. 1A′ to 1G′ illustrate the top views of thefirst embodiment of the first LED array 1. The method for manufacturingthe first LED array 1 comprises steps of:

-   -   1. Providing a temporary substrate 11, and forming an epitaxial        structure thereon. The epitaxial structure comprises a first        conductive semiconductor layer 12, an active layer 13, and a        second conductive semiconductor layer 14 as illustrated in FIGS.        1A and 1A′.    -   2. Next, forming multiple trenches 15 by partially etching the        epitaxial structure in the first area (I) and the second area        (II), and the epitaxial structure not etched forms multiple flat        planes 16, and the epitaxial structure of the third area (III)        is not etched as illustrated in FIGS. 1B and 1B′.    -   3. Forming a conductive connecting layer 17 on partial regions        of the flat planes 16, and the area of the flat planes 16        uncovered by the conductive connecting layer 17 forms multiple        pathways 18 as illustrated in FIGS. 1C and 1C′.    -   4. Forming a first isolation layer 19 on part of the conductive        connecting layer 17, the multiple pathways 18, and the side wall        of the multiple trenches 15, while the conductive connecting        layer 17 in the third area (III) and part of the conductive        connecting layer 17 in the first area (I) are not covered by the        first isolation layer 19. The conductive connecting layer 17 not        covered by the first isolation layer 19 in the second area (II)        is defined as a conductive region 20 as illustrated in FIGS. 1D        and 1D′.    -   5. Forming a crossover metal layer 21 on the first isolation        layer 19, the conductive region 20, in multiple trenches 15, and        on the conductive connecting layer 17 in the third area (III). A        part of the conductive connecting layer 17 in the first area (I)        is not covered by the crossover metal layer 21 in order to        electrically connect the second conductive layer 23 with the        second conductive semiconductor layer 14 in the following steps.        The region which is not covered by the crossover metal layer 21        in the second area (II) nearby the conductive region 20 is used        for electrical isolation as illustrated in the FIGS. 1E and 1E′.        Part of the crossover metal layer 21 in the first area (I)        extends to multiple trenches 15 and electrically connects to the        first conductive semiconductor layer 12. The crossover metal        layer 21 on multiple flat planes 16 and the pathways 18 in the        first area (I) is electrically isolated from the second        conductive semiconductor layer 14 by the first isolation layer        19. The crossover metal layer 21 on the conductive region 20 in        the second area (II) electrically connects with the second        conductive semiconductor layer 14 by the conductive connecting        layer 17. Part of the crossover metal layer 21 in the second        area (II) extends to multiple trenches 15 and electrically        connects to the first conductive semiconductor layer 12. The        crossover metal layer 21 on multiple flat planes 16 and the        pathways 18 in the second area (II) is electrically isolated        from the second conductive semiconductor layer 14 by the first        isolation layer 19. The crossover metal layer 21 in the third        area (III) is electrically connected with the second conductive        semiconductor layer 14 by the conductive connecting layer 17.    -   6. Forming a second isolation layer 22 on the crossover metal        layer 21 and the region a in the second area (II). But part of        the conductive connecting layer 17 in the first area (I) is not        covered by the second isolation layer 22 as illustrated in the        FIGS. 1F and 1F′.    -   7. Forming the second conductive layer 23 on the second        isolation layer 22 and part of the conductive connecting layer        17 as illustrated in the as illustrated in the FIGS. 1G and 1G′.    -   8. Forming a bonding layer 24 on the second conductive layer 23        which is bonded with a permanent substrate 25 by the bonding        layer 24 as illustrated in the FIG. 1H.    -   9. Removing the temporary substrate 11 to expose the first        conductive semiconductor layer 12 and roughening the surface of        the first conductive semiconductor layer 12. Next, etching        multiple pathways 18 from the first conductive semiconductor        layer 12 until the first isolation layer 19 is revealed in order        to form N light-emitting diode units. Among the N light-emitting        diode units, the first light-emitting diode unit locates in the        first area (I), the second to the (N−1)^(th) light-emitting        diode units locate in the second area (II), and the N^(th)        light-emitting diode unit locates in the third area (III). At        last, forming a first electrode layer 27 on the roughed surface        of the first conductive semiconductor layer 12 in the N^(th)        light-emitting diode unit. Thus an LED array 1 having N        light-emitting diode units electrically connected in serial by        the crossover metal layer 21 is formed as illustrated in FIG.        1I.

The second embodiment discloses a second LED array 2 having threelight-emitting diode units. FIGS. 2A to 21 illustrate the crosssectional views and the FIGS. 2A′ to 2G′ illustrate the top views of thesecond embodiment of LED array 2. The method for manufacturing thesecond LED array 2 comprises steps of:

-   -   1. Providing a temporary substrate 11, and forming an epitaxial        structure thereon. The epitaxial structure comprises a first        conductive semiconductor layer 12, an active layer 13, and a        second conductive semiconductor layer 14 as illustrated in FIGS.        2A and 2A′.    -   2. Next, forming multiple trenches 15 by partially etching the        epitaxial structure in the first area (I), the second area (II),        and the third area (III), and the epitaxial structure not etched        forms multiple flat planes 16 as illustrated in FIGS. 2B and        2B′.    -   3. Forming a conductive connecting layer 17 on partial regions        of the flat planes 16, and the area of the flat planes 16        uncovered by the conductive connecting layer 17 forms multiple        pathways 18 as illustrated in FIGS. 2C and 2C′.    -   4. Forming a first isolation layer 19 on part of the conductive        connecting layer 17, the multiple pathways 18, and the side wall        of the multiple trenches 15. The conductive connecting layer 17        in the second area (II) and the third area (III) which is not        covered by the first isolation layer 19 are defined as a        conductive region 20 as illustrated in FIGS. 2D and 2D′.    -   5. Forming a crossover metal layer 21 on the first isolation        layer 19, the conductive region 20, and in the multiple trenches        15 except those in the third area (III). A part of the first        isolation layer 19 in the first area (I) is not covered by the        crossover metal layer 21 in order to electrically isolate the        first conductive layer 26 from the second conductive        semiconductor layer 14 in the following steps. The first        isolation layer 19 in multiple trenches 15 and flat planes 16 is        not covered by the crossover metal layer 21 in order to        electrically isolate the first conductive layer 26 from the        second conductive semiconductor layer 14 in the following steps        as illustrated in the FIGS. 2E and 2E′. A part of the crossover        metal layer 21 in the first area (I) extends to multiple        trenches 15 and electrically connects to the first conductive        semiconductor layer 12. The crossover metal layer 21 on multiple        flat planes 16 and the pathways 18 in the first area (I) is        electrically isolated from the second conductive semiconductor        layer 14 by the first isolation layer 19. The crossover metal        layer 21 on the conductive region 20 in the second area (II)        electrically connects with the second conductive semiconductor        layer 14 by the conductive connecting layer 17. A part of the        crossover metal layer 21 in the second area (II) extends into        the multiple trenches 15 and electrically connects to the first        conductive semiconductor layer 12. The crossover metal layer 21        on multiple flat planes 16 and the pathways 18 in the second        area (II) is electrically isolated from the second conductive        semiconductor layer 14 by the first isolation layer 19. The        crossover metal layer 21 on the conductive region 20 in the        third area (III) electrically connects with the second        conductive semiconductor layer 14 by the conductive connecting        layer 17. Besides, the region b in the second area (II) and the        third area (III) adjacent to the conductive region 20 is not        fully covered by the crossover metal layer 21 which is used for        electrical isolation.    -   6. Forming a second isolation layer 22 on the crossover metal        layer 21, the part of the first isolation layer 19 in the first        area (I), and on the region b which is not fully covered by the        crossover metal layer 21 in the second area (II). The second        isolation layer 22 does not cover the inner side of the trenches        15 in the third area (III), the first isolation layer 19 of the        multiple flat planes 16, and the region b which is not fully        covered by the crossover metal layer 21 in the third area (III)        as illustrated in the FIGS. 2F and 2F′.    -   7. Forming the first conductive layer 26 on the second isolation        layer 22, in the multiple trenches 15 in the third area (III),        on the first isolation layer 19 of the flat planes 16, and the        region b which is not fully covered by the crossover metal layer        21 in the third area (III) as illustrated in the FIGS. 2G and        2G′.    -   8. Forming a bonding layer 24 on the first conductive layer 26        which is bonded with a permanent substrate 25 by the bonding        layer 24 as illustrated in the FIG. 2H.    -   9. Removing the temporary substrate 11 to expose the first        conductive semiconductor layer 12 and roughs the surface of the        first conductive semiconductor layer 12. Next, etching multiple        pathways 18 form the first conductive semiconductor layer 12        until the first isolation layer 19 is revealed in order to form        N light-emitting diode units. Among the N light-emitting diode        units, the first light-emitting diode unit locates in the first        area (I), the second to the (N−1)^(th) light-emitting diode        units locate in the second area (II), and the N^(th)        light-emitting diode unit locates in the third area (III). Next,        etching the first conductive semiconductor layer 12 in the first        area (I) without the crossover metal layer 21 until the        conductive connecting layer 17 is revealed, and forming a second        electrode layer 28 on the conductive connecting layer 17. Thus        an LED array 2 having N light-emitting diode units electrically        connected in series by the crossover metal layer 21 is formed as        illustrated in FIG. 2I.

The temporary substrate 11 described in the above first and secondembodiments is made of, for example, gallium arsenide (GaAs), galliumphosphide (GaP), sapphire, silicon carbide (SiC), gallium nitride (GaN),or aluminum nitride. The epitaxial structure is made of an III-V groupsemiconductor material which is the series of aluminum gallium indiumphosphide (AlGaInP) or the series of aluminum gallium indium nitride(AlGaInN). The conductive connecting layer 17 comprises indium tinoxide, cadmium tin oxide, antimony tin oxide, indium zinc oxide,aluminum zinc oxide, and zinc tin oxide. The first isolation layer 19and the second isolation layer 22 can be made of an insulating materialcomprises silicon dioxide, titanium monoxide, titanium dioxide,trititanium pentoxide, titanium sesquioxide, cerium dioxide, zincsulfide, and alumina. The first conductive layer 26 and the secondconductive layer 23 can be made of silver or aluminum. The bonding layer24 is an electrically conductive material made of metal or its alloyssuch as AuSn, PbSn, AuGe, AuBe, AuSi, Sn, In, Au, or PdIn. The permanentsubstrate 25 is a conductive material such as carbides, metals, metalalloys, metal oxides, metal composites, etc. The crossover metal layer21 comprises metal, metal alloys, and metal oxides.

Although the present application has been explained above, it is not thelimitation of the range, the sequence in practice, the material inpractice, or the method in practice. Any modification or decoration forpresent application is not detached from the spirit and the range ofsuch.

What is claimed is:
 1. A light-emitting structure comprising: a firstepitaxial unit; a second epitaxial unit disposed next to the firstepitaxial unit; a crossover metal layer comprising a first protrudingportion laterally overlapping the first epitaxial unit and the secondepitaxial unit wherein the first protruding portion is electricallyconnected with the first epitaxial unit and the second epitaxial unit; aconductive connecting layer disposed below the first epitaxial unit andthe second epitaxial unit and surrounding the first protruding portion;and an electrode arranged on the conductive connecting layer.
 2. Thelight-emitting structure of claim 1, wherein the electrode iselectrically connected with the conductive connecting layer andlaterally overlaps the first epitaxial unit and the second epitaxialunit in a cross-sectional view.
 3. The light-emitting structure of claim2, wherein the electrode, the first epitaxial unit, and the secondepitaxial unit are disposed in a row in a cross-sectional view.
 4. Thelight-emitting structure of claim 1, wherein the first protrudingportion is devoid of passing through the first epitaxial unit.
 5. Thelight-emitting structure of claim 1, wherein the conductive connectinglayer has a portion not covered by the first epitaxial unit.
 6. Thelight-emitting structure of claim 1, further comprising a conductivelayer disposed below the crossover metal layer wherein the cross metallayer comprises a second protruding portion entering the secondepitaxial unit.
 7. The light-emitting structure of claim 6, furthercomprising an isolation layer formed between the crossover metal layerand the conductive layer.
 8. The light-emitting structure of claim 6,wherein the first protruding portion has an elevation substantiallyequal to that of the second protruding portion.
 9. The light-emittingstructure of claim 6, wherein the conductive layer comprises a portionarranged under the crossover metal layer.
 10. The light-emittingstructure of claim 6, wherein a width of the conductive layer issubstantially equal to that of the light-emitting structure.
 11. Thelight-emitting structure of claim 1, further comprising a firstisolation layer arranged between the conductive connecting layer and thefirst protruding portion.
 12. The light-emitting structure of claim 1,further comprising a roughened surface on top surfaces of the firstepitaxial unit and the second epitaxial unit.
 13. The light-emittingstructure of claim 1, further comprising a permanent substrate under thefirst light emitting unit, and a bonding layer disposed between thepermanent substrate and the first epitaxial unit.
 14. The light-emittingstructure of claim 13, wherein the first protruding portion iselectrically connected with the bonding layer.
 15. The light-emittingstructure of claim 1, wherein the first epitaxial unit or the secondepitaxial unit comprises an epitaxial structure, and the epitaxialstructure comprises a first conductive semiconductor layer, an activelayer, and a second conductive semiconductor layer.
 16. Thelight-emitting structure of claim 15, wherein the first conductivesemiconductor layer contacts the first protruding portion.
 17. Thelight-emitting structure of claim 16, wherein the conductive connectinglayer is electrically connected with the electrode.
 18. Thelight-emitting structure of claim 1, wherein in a top view, theconductive connecting layer comprises a plurality of openings, and thefirst protruding portion is disposed in one of the plurality ofopenings.
 19. The light-emitting structure of claim 18, wherein theplurality of openings is arranged in a matrix.
 20. A light-emittingstructure comprising: a light-emitting unit; a crossover metal layercomprising a protruding portion laterally overlapping the light-emittingunit, wherein the protruding portion is electrically connected with thelight-emitting unit; a conductive connecting layer disposed below thelight-emitting unit and surrounding the protruding portion; and anelectrode arranged on the conductive connecting layer; wherein a topsurface of the protruding portion contacts a surface of thelight-emitting unit or the protruding portion is devoid of passingthrough the light-emitting unit.